Apr 10, 2010 7:15pm
Re: Problems downloading PDFs
I think I have a similar problem sometimes, so on the main description page I got into the habit of not left clicking on the file, bringing up a dialogue box asking where to save to BUT INSTEAD right click and choosing "save as" from the context menu (the pop up menu)
I suspect that could well be the same as going to the HTTP page and doing it there.
A problem with going to the HTTP is some file names are too long, so you dont see the file extension, unless you hover the mouse cursor over each file name.
I find often a left click on a URL fails to do anything, the work around is Right Click and from the Context Menu clicking on "open link in a new tab"
All the above problems I think stem from two things, I fix friend's PC's some have dial up, and I have a network of PCs on flat out DSL.
One reason for the issue is incompatibilities between web sites and browsers, stemming from software on both sites and browsers being at different stages of security updates, and some sites having clashes as their site builders use software tricks to be different and attract more visitors.
In some cases, your AV software might fail to clear the URL for safety, the databases the AV software checks, can be considered to be dynamic, constantly being updated and these databases could be overloaded at times. The problem WILL get worse because NOBODY has yet found a way to eliminate the virus writers. Today, few virus are written to do harm, instead its all about STEALING data such as banking ID and passwords.
But the main reason for download issues is other software on your PC running in the background, AV, Firewalls, checking email every 5 minutes automatically, applications including AV, Browsers, Windows Up Date, PDF readers etc etc going on line to check for updates.
When downloading a big file, it comes to you in packets, each packet as it arrives must be checked for completeness and accuracy by your CPU running a checksum calculation, just one bit in the packet, a 1 rather than a 0 means the calculation fails and CPU/Browser asks the File Server to resent the packet.
And that can and does happen more than once on the same packet. Coupled with other software on your PC running in the background and some software checking for other things on the WWW, its not surprising that packet verification checksum calculations can fall behind, (and even mistakenly fail the check) then with each failure, a request goes out for a replacement packet, until it arrives, the CPU is still checking incoming packets, it will also be doing the same for packets coming down in response to other software's requests for news of latest updates, email, and maybe you are doing other things on the WWW while
files are downloading in the background.
the browser must go nuts juggling its resources, keeping track of incoming packets, missing packets, checking them, asking for replacements, or asking for the next one, waiting for replacements to arrive and then saving them in correct sequence, all this while AV is watching and checking, the firewall doing the same
My PCs run Windows and Unbuntu, one PC has a slow CPU, I literally spent hours monitoring downloads, CPU and RAM usage to learn about such things.
One thing a lot of people dont know, is when STREAMING a movie from the WWW there
is a high number of packet checksum errors allowed without correction, otherwise streaming a video won't work and anyway you dont notice misplaced 1 & 0 in steaming video and audio unless its excessive. All file packets downloaded and not streamed MUST be perfect, otherwise your software just spits it out as unusable, just one bit 0 or 1 incorrect is all it takes to be a failed download.
Dial Up was NEVER meant for big file downloads, mainly it was for email, small attachments and for surfing the WWW, shopping, researching. DSL had to come in, in order to cope with all the file downloading we have today
fixes, and workarounds.
Other software running in the background on your PC, can and does affect download speeds especially on dial up. Check out the software on http://www.whatsrunning.net/whatsrunning/order.aspx
I use the free version to see what software runs in the background on my PCs, everybody I tell about "What's Running" comes back to me saying they were amazed with what they learnt, everybody has stuff running that they never authorised rarely used software to start up, when their PC boots up.
Use Windows Task Manager, "Process" tab to check what is hogging PC resources, e.g for the CPU column, click at the top (maybe click twice) and it orders each process, in order of CPU usage. If you know what you are doing, you can shut down some processes, Google Desktop search is one to shut off temporarily, look for Windows Update, and other updater, they will comeback when you reboot your PC. I came across a HP updater once, while it was running in the background, I prevented it from accessing the WWW, it then grabbed all the CPU it could, trying to access the WWW, my point is, if I had not spotted it on the new HP PC, it would always expect priory on WWW access
, and cause other downloads to slow or fail.
When I had dial up, and big IA downloads, I shut off my AV checking, most of the other software running, and ONLY did downloading, no surfing, I stayed on the ONE web site. After finishing downloading, I started up my AV, and scanned the downloads folder, then rebooted my PC.
It even might pay to have a old PC, just for downloading, without AV or firewall, then doing AV checks when transferring files to your main PC. If your old PC gets virus infected, just do a system restore from a restore CD.
I live 350-metres from New Zealand's tallest radio transmitter (check out my uploads re local cell towers)the tower is 220 metres high and can cover the Southern Pacific (can, but I think SW is no longer being transmitted)it transmits a number of commercial stations as well as Radio NZ National Radio.
In effect, its like music on hold when you use the telephone, when I moved into my home in 1993, I removed the old dial phone and put in a push button phone. Every time I tried to push a button, all the RF in the air, went down my finger and crashed the phone line, I had to resort to a 6 inch long dowel for dialling. Next day, Telecom installed a RF suppressor. (Before me, there was a old lady living here, hence the dial phone.)
Nowadays music on hold is mostly gone, as we have digital phones, but there is still issues with WWW Dial
Before I got DSL I had dial up. One day my mates at the ISP ran speed checks and found I had the fastest Dial Up in the Bay.
Its underground phone cable, then a 20-metre overhead cable from the pole to my home.
Inside, I had replaced all the old phone wire (1960s figure 8) for Telecom approved 3 pair, except I had used the same gage in Computer Data rated shielded cable.
The demarcation point on the wall, there I put my dial up phone jackpoint, AND a switch to cut off all my other telephone jackpoints. I also had a phone plugged in to my PC dial up modem.
People with dial-up, BELIEVE ME, it pays to unplug EVERY telephone in your home while using the line for dial up. The ISPs recommend it, and they are CORRECT.
A phone line is looped from jack point to jack point, at each jack point the wire is terminated on one set of IDC connectors, and taken out from a second set.
What I have done for some friends, is run a line direct from demarcation point, to their dial up jack point, and a second line, from demarcation point looping around the phone jack points.
For joining cable, or inserting RF suppressors, Telecom uses IDC joiners, even 3 way for Y junctions. In effect, the wires joined point in the same direction, so signal must do a 180 degree turn in the IDC joiner.
And thus with Dial Up signal, the signal sort of echoes, imagine a Radar signal going into the connector, rather than doing the 180 degree turn into the other wire, the radar signal bounces back to the transmitter, in dial up that means slower WWW access.
What I have been doing, is twisting wires together and soldering, so signal travels in a straight line. My friend on dial up, went from 36 to 42 on a 56K modem. (42 is the maximum you can expect of 56K)
For soldering, there is only one viable way of removing the insulation from thin gage inside phone wire, for that I had a old soldering iron, a small piece of steel and use the hot iron to scrape/melt the insulation of the wire while it lies on the bit of scrap steel. (after soldering, use proper insulation tape to insulated, I rarely use heat shrink insulation due to not enough room to have it on the wire before I solder it)
The same goes for DSL, recently I was upgraded to DSL2 (NZ is 10-years behind the USA)The best download I got was about 6000Kbps so after soldering the connections, I went to 11,000 and the modem says it can now attain 13000.
The modem is across the upstairs room from the phone line demarcation point, and its a coincidence that the demarcation point is exactly in line with the pole outside and modem jack-point. And thus the cable between demarcation point and jack point does not run around the walls, its goes direct, 600-mm below the ceiling, supported by a length of curtain wire. I dont know if the speed increase is due to my elimination of the radar echo effect but something I did resulted in the improvement.
To the modem jack point, connections are soldered, the modem jack point uses IDC and from there, my line loops out to the telephones. Inside those jack points, I soldered incoming and outgoing wire, with another wire/tail which forms the Y junction, and connects to the jack points IDC connectors.
I hope those with dial up will try my ideas, the minimum you should do, is UNPLUG every phone on the phone line when on liner vial dial up.
This post was modified by Time Traveller on 2010-04-11 01:55:25
This post was modified by Time Traveller on 2010-04-11 02:15:34